Grinding fixture for thread-cutting chasers



NOV. A. F. BREITENSTEIN 1,830,189

I GRINDING FIXTURE FOR THREAD CUTTING CHASERS Filed Oct. 25, 1929 5 Sheets-Sheet 1 63' a -4 5e 3 w 55 Q 5; a L *E y 1931- A. F. BREITENSTEIN 1,830,189

GRINDING FIXTURE FOR THREAD .CUTTING CHASERS 7 Filed Oct. 25, 1929 5 Sheets-Sheet 2 zo I a9 Z3 I Z/ I Nov. 3, 1931. A. F. BREITENSTEIN 1,830,189

GRINDING FIXTURE FOR THREAD CUTTING CHASERS Filed 001;. 25, 1929 5 Sheets-Sheet 4 A. F. BREITENSTEIN 1,830,189

Nov. 3, 1931.

GRINDING FIXTURE FOR THREAD CUTTING CHASERS Filed Oct. 25, 1929 5 Sheets-Sheet 5 mmfiiiiiill IIIIIIIIIIIIIIIIIII Iilium one to-the other for; the respectivecharnferupon their cutting-faces; or viceversa, 1 order or sequence of thetwo operations being Patented Nov.

U PATENT o F cE ALBERT r. .Bnnirnnsrnm, or livnw HAVEN, coimnc'rreur, vnssreivon TO THE genomn'rmomoon,coivrremr, or vnw oonivnorreur, VA CORPORATION enrivnmarxxrunn FOR THREAD-comma cHAsEns Applicatio flledoctoher 25,1929; Serial 1105402534. I

Heretofore thechamfers and the cuttingv faces of threadingechasers, such as are used inselfeopening die-heads and collapsing taps andkindred tools, haveibeen ground in separate fi'xtures5'involving considerable initial expense-for the'fixturesfthemselves and time and labor in transferring. the chasers from ing'and face-grindingoperations.

The object'- of :my. present invention is to v produce a single eunitary fixture adapted to be set for these respeotivegoperations, so that:

after a given number or batch-of Chasers have had the, chamfergrinding operation performed upon them; the same fixture may be set for having the samelot-of chasers grourlild rt e immaterial. I Myimproved ed .to the dual purpose of face-grinding; as

well as" chamfer-grinding. v

' ith these 'endsinview, my invention consists in a grinding-fixture for thread-cutting" *chasers having a head swiveledto turn in a horizontal plane, a horizontallongitudinallyadjustable carrier-bar "carriedby the said head and adapted to be axially rocked in a vertical plane, and a chaser-holder carried by the said bar.

Mv invention furthercconsists 'in a grinding-fixture having certain details of construc tion and combinations of parts as will be herein after described and pointed. out the claims.- 7 1 I l/Vith reference now to the draw;ings,.Figs

1 to 4 inclusivesh'ow improved fixture as set for chainfer-"grin'ding chasers'of, the milled wtypeethefcommon term'employed for chasershav'ing' straight cutting-teeth.

In the accompanying drawings gFigjl is a view injfr'ont elevation of my improved fixture as set for grinding the cham fers of milled type thread-cutting Chasers, the fixture being shown as mounted upon a suitable grinding-machine base;

." Fig 2 is a planiview thereof;

is a viewqthereof in left-hand endelevation;

on the line 4-4: of Fig. 1;

Fig. 5 is a, view of-the fixture in front ele- 'tary fixture isthus adapt- -fiXi1lll'G as set for grlndlng the chamfers of chasershav ng concave cutting-teeth;

Fig. 4 transverse sectional View taken vation as set for-grinding the hook-like cutting faces of certain chasers; V

Fig. 6 is a view thereof in right-hand end elevation; v I

Fig. 7- is a detached view in end elevation of a milled type chaser with a hook-like cut ting-face; v Fig. 8 is a face view thereof;

Fig. 9 is a face'view of the fixture as set for grlnding the chamfersof chase-rs having convex cutting-teeth;--

F 1g 10 is a View thereof in left-hand end elevation;

F igi ll is a detached end view of such a chaser? p v v ig- 12 is'a face view'thereof; I I Fig. 13-15: a plan view of my im d Fig. 14 is a view-- thereof in left-hand end elevation; J a i Fig. 15is a detached view in end elevation of: such achaser; 1

Fig. 1-6 is a face view thereof; and

Fig. 17 is a detached plan ,view of the cylindrical carrier-bar of the fixture,

Asherein shown, my improved fixture is provlded with a base 20 adapted to be attached by bolts 21 to-the sliding-table 22 0f a -grinding-machine of any approved type.

The table 22 is mounted for longitudinal movement upon a sub-table 23 which, in turn,

is mounted for transverse movement upon a bed 24.. The base 20 is formed with an upstanding circular boss 25 having a flat upper face providing a bearing for the flat under 7 face of a circular swivel-head 26 having a heavy centrally-depending trunnion 2'1 formed with anannularperipheral groove 28 receiving thepointed end of a locking-screw 29 having a wing-head 30, the trunnion 27 fitting within a bearing-opening 31 formed in and, concentric with the upstanding boss 25. The trunnion, andhence the swivel-head 26, is held against upward displacement in theboss 25 by means of an anchoring-plate 32 secure'dto its lower face by screws'33, and

' recess34, as shown in Fig. 1 of the drawings.

the swivel-head 26 at the desired angle When the swiVel-head26 isturned, theends of the'plate 32 sweep over the upper wall of the recess34. Under this construction, the

swivel-head '26, when unlocked, 'may be.

turned in either direction in the horizontal plane upon the.1.upstanding boss "o1 the ing by the locking-screw 29. 7 To guide. the user of the fixture in setting with respect to the base 20, the upstanding boss 25 is furnished with a segmental scale 60 and the periphery of the'swivel-h'ead 26 with diametrically-opposite index-lines 61, as shown in Fig. I. I

The upper face of the swivel-head 26 is formed atone side of its center with a heavy and preferably integral mounting-block 85 havin'ga horizontal cylindrical bearing-opening 36 and'longitudinally split as at 37 to adapt it to be sprung by a clamping-screw 38' base 20. Whenset, it is locked against turnso as to grip aheavy cylindrical carrier-bar It 39 in any desired position therein of rotary .orLlOngitudinal adjustment.

For the purpose of readily determining the longitudinal adjustment of the carrier-bar 39 in the mounting-block 35, it is provided upon its periphery-"with a longitudinal scale 40 which is, read in connection with thesmooth inner facel41, shown'in "Fig. 1,o:tthe block;

:The carrier-bar 39 is alsoprovided with an index-line 42 (Fig. .2) "which is read in conjunction withasegmenta-l scale 43' formed upon thesmoothouter face 44,*shown in Fig.

- 3, of the block.

At the end of the car'rier-bar opposite the scale 40 already described, it is forinedwith two pairs of diainetrical holes 45 and 46, 47 and 48 the holes 45and 47 being larger than their complementary holes 46 and 48. holes45 and 47 receive,- according to the setting of the fixture,a mounting-bolt 4Q,- while the holes 46 and 48 receive, according to thesetting of the fixture, a stop-pin 50 adapted to be set into either hole, both (i. e.', the holes 46 and 48) of which are provided with setscrews 51 f0r firmly holding thesaid stoppin in place. r I

The holes 45 and 47 aforesaid provide tor the"'rigidattachment to the bar, in the hori Zontalor vertical position,as the case maybe, of a chaser-holder 52 formed in its inner end and in one of its sides respectively with threaded bores 52 and 52 positioned at right angles to each othecforthereception of the mounting-bolt 49, according to the desired position of the holder'w'ith respect to the bar 39. The said holder isbifurcated or splitf inward from itsouter end'bya deep centrallylocated Y -shaped slot 53 enlarged at its outer endfto form a chaser-receiving socket-54y niovable sub-table 23, the fixture is l-chaser back and forth across 1,sso,1ee

as shown'in Figs. 1 to '4 inclusive, the chaserholder 52'is fastened in a' vertical position uponthecylindrical carrier-bar 39 by means ofthe screw 49 which is passed upward into ,1ts threaded bore 52? through the diametrical hole 47 in the bar. Thestop-pin 50 is set into-the hole 48 and secured therein by its set-screw51. "A milleditype chaser, such as 62 (Figs-7- and 8), is nowset into the socket teeth into engagementwith the adjacent face of the stop-pin 50. .The clamping-screw 57 is nowturned by itswing-head 58 to firmly clamp the" chaser; 'in thisl fposition. The

swivel-head 26 islnowjunlockediand' swung in a horizontal plane f in one direction or the other- (dependent upon whether the chaser is a right-hand. orlefthan'd chaser) to set it'to' the clearance-angleiat whichait is desired to grind the cha1nfer,'*this' setting oft he swivelhead being determined by the reading of diametrically-opposite indexelines' fil upon the swivel' head 26 with; respect to a seg-i mental scale 60 upon -theboss'25. of the base 20. As soon as the swivel-head has been set,

it is relocked by the screw 29. The setting operation is started. "Thetable 22 carrying the unitary fixture, is nowf inovedso as to bring the chamferof.v the chaser 621into en- I 54, in which it ispositioned by bringing its of the; swivel-head may, of course, be effected gageinent withthe periphery of a grindingwheel 63. 'By means of the transverselyn'ow transversely moved so as to pass the chainter of the the periphery of thegrindingwheel aforesaid. "The chamfer-clearanceangle of thechaser being open ated upon is thus determined by. setting the swivel-head 26 with respect to the base 20 and locking it in place by means of the screw 29. The desired slopeof the chamfer-angle is secured in the usual manner by raising or lowering either the grinding-wheel 63 or the bed 24, or'both, with respect to each other. The chaser in the holder having had its chainfer 64 ground, is removed andreplaced by a corresponding chaser, and so on, until all of the chassis of anygivenlot, have been thus operated'upon. i i

In order to grind the cutting-faces 65 of the chasers, the mounting-screw 49, is unscrewed frorn'the, chaser-holder 52 .and the same turned down into a horizontal position, with its axis parallel with the carrier-bar 39, as shownin Fig. 5,'and the screw 49"passed through the hole thereinand screwed into the threaded bore52 ofthe: chaser-holder for rigidly mounting the same upon the carrier-bar 39. The stop-pin is now removed from the hole 48 in the said barand' the chaser i set into the socket 554 in the chaser-holder in'the positionshownin. Figs. 5 andfi and ting of the'bar at'the angle desired may be eifected'at any time before the actual grind-- ing isbegun. At this time, as it will' be understood, the swivel head 26 is set at zero and locked thereat- The sub-table 23 carry} ing the fixture is now moved laterally to cause the cutting-face 0f the chaser to be brought into engagement with a side-face of the grinding-wheel 63. The sliding-table 22 is now reoiprocated to cause the cutting-face of the chaser to move back and forth with'respect to the side-face of the grinding-wheel. The set-up of the fixture, as above described, for grinding the cutting-faces of the chasers, is substantially the same for all common forms of chasers, such as milled type chasers, Figs. 7 and 8; convex chasers, Figs. 11 andl2; andconcavechasers, Figs. 15and J6: and so on. f r

In order to use my improved fixture for grinding the chamfers of convex-toothed chasers (Figs. 11 and 12) which are primarily designed for-use in collapsing taps, the care rier-bar 39'is appropriately positioned lon- "gitudinally in the mounting-block 35, as shown in Figs. 9 and 10.. The chaser-holder 52 is fastened in vertical'position to the said bar by means of the screw 49. A chaser is then clamped in position in the chaser-holder i "and brought to bear against the stop-pin 50. The bar 39 is now rocked in a vertical plane so as to cant the chaser-holder and chaser to the required angle to produce the desired chamfer-oleara-nce angle and locked in such.

position. The table '22 is then moved longitudinally,

tance of. the chamfer-being ground from the h vertical axis of the swivelhead 26. Thus, if

carrying with it the unitary fixture, until the chamfer' of the chaser is the'carrier-bar 39 is so adjusted as to bring the chamfer near the said vertical axis, a very marked curvature willbe ground upon the ohamfer, whereas, if the said bar is adjusted longitudinally with respect to the swivelhead, so as to locate the chamfer remote from the vertical axis of the said head, a relativelyslight convexity will be ground "upon the chamfer. 1 H

To set my improved fixture for grinding concave-toothed chasers of the type shown in Figs- 15 and .16, the fixture is set, as shown inFigs. 13 and 14, so as to bring the chamfer 64 of the chaser in a position facing toward the vertical axis of the swivel head 26. Then the swivel-head is oscillated back and forth in thehorizontal plane by the user, a concave grindmg of the chamfer results. It will be understood that the sequence of adjustments in setting the fixture to do its different kinds of work may be varied from the order herein set forlh, it only being necessary that the ultimate adjustments be made before the cutting is begun. It may also be stated that with the smaller types of milled type chasers, they may have theircuttingfaces ground by merely turning them in the chaser-holder itself, without resorting to detaching the same from the carrier-bar and relocating it thereupon.

1. A grinding-fixture for thread-cutting chasers having a disk-shaped head swivel'ed to turn in a horizontal plane, 'a'horizontal longitudinally-adjustable carrier-bar extending diametrically over and carried by the said head and adapted to beaxially rocked in a vertical plane, and a chaser-holder located above and carried by the *saidbar. I

.2. A grinding-fixture for thread-cutting chasers having a disk-shaped head swiveled to turn in a horizontal plane, a horizontal longitudinally-adjustable carrier-bar extending diametrically over and carried by the said head and adapted to be axially rocked in a vertical plane, and a removable chaser-holder located above and carried by the said bar.

3. A grinding fixture for thread-cutting chasers having a disk-shaped head swiveled to turn in a horizontal plane and provided with an upstanding clamping-member formed'with a horizontal cylindrical axial passage, a horizontal:longitudinally-adjustable carrier-bar adapted to be clamped in the said passage so as to extend diametrically over the said head'and adapted to be axially rocked therein in a vertical plane, and a chaser-holder located above and carried by the said bar.

4. A grinding-fixture for thread-cutting chasers having a disk-shaped head swiveled to turn in a horizontal plane, a horizontal longitudinallyadj ustable carrier-bar extending diametrically over and carried by the said head and adapted to be axially rocked in a grinding-wheel-- vertical plane therein, and a chaser-holder located above and carried by the said bar and adaptedto be reversibly secured thereto for presenting chasers'in different positions to a 5. A grinding-fixture for thread-cutting Chasers having a disk-shaped head swiveled to. turn in a horizontal plane, a horizontal longitudinallyadjustable carrier-bar extending midiametrically' over and carried by the said head and adapted to be axially rocked therein in a vertical plane, and a removable chaserholder located above and carried by the said bar and reversible in positionthereon for changing the presentation of the Chasers with respect to a grinding-wheel, and removable means applied to the said barindependent of the said holder for a chasertherein.

6. A grinding-fixture for thread+cutting 5f ch'asers, comprising a base adapted to be secured to the table ofa grinding-machine and formed with a vertical cylindricalsocket, aswiveled disk-shaped head provided with a depending trunnion fitting withinthe said ao socket with capacity for turning movement in a horizontal plane with respect to the said base, a horizontal longitudinally-adjustable carrier-bar extending diametrically over and carried by the said swiveled head and adapted to be axially rocked with respect thereto in a vertical plane, and a chaser-holder located aboveand-carried by the said bar.

8. A. grinding-fixture for thread-cutting chasers, comprising a base adapted to be EUsecured to the table of a grinding machine and formed with a vertical cylindrical socket,

a swiveled disk-shaped head provided with a depending trunnion fitting within the said socket with capacity for turning movement in the horizontal plane with respect to the said base, means for locking the swiveled head in various positions of horizontal adjustment with respect to the said base, ahorizontal longitudinally-adjustable carrier-bar extending diametrically over and carried by the said swiveled head and adapted to be axially rocked with respect thereto in a vertical plane, means for locking the said bar in the said swiveled head inany one of, its positions of axial and longitudinal adjust- V gauging the position of by the said bar. a I I 9.- A grinding-fixture for thread-cutting chasers having a head swiveled to turn in a horizontal plane, a horizontal longitudinallyadjusta-ble carrier-bar carried by the said head and adapted to be axially rocked in a vertical plane, means for locking the said head and carrier-bar in any one'of their adjusted positions, and a removable chaserholder carried by the said bar. and entered by twothreaded bores arranged at right angles to each other for the reception or" a bolt by means of which it is rigidly'securedin either one of two positions with respect to the bar for changing the presentation'of a chaser ment therein, and" a chaser-holder carried held in it to the action of the grinding-wheel.

In testimony whereof, I- have signed this specification. a V

ALBERT BREITENSTEIN. i 

